Switches embodied as a circuit-breaker, load-break switch or disconnecting switch are known which have one or a plurality of current conductors of a polyphase alternating current, a metal encapsulation accommodating the current conductor or the current conductors, and at least one cooling element by which heat generated during the operation of the switch in a high-voltage installation on account of current losses in the current conductor or in the current conductors is removed from the encapsulation. If the switch is intended for an installation loaded with high currents, for instance an outgoing generator line, then at rated high voltages on the order of between approximately 1 and 70 kV it can carry rated currents that lie, for example, between 6 kA and 40 kA. If it is used in a gas-insulated encapsulated switchgear installation of a high-voltage system, then at rated voltages on the order of between approximately 70 and 800 kV it can carry rated currents of, for example, 2 to 6 kA.
At rated currents, the current conductor (e.g., tubular in shape) can experience a high degree of heating on account of resistive losses. The current conductor encompasses the rated current path of the high-voltage switch since greater current losses and therefore also greater formation of heat than in the material of the current conductor can occur there on account of contact locations. During rated current operation, a maximum temperature prescribed by standards, for example 105° C., and thus a resultant maximum temperature increase, for example 65° C., should not be exceeded, whereby the maximum rated current of the switch is limited. In order to keep the operating temperature of the current conductor below the permissible maximum temperature, therefore, the heat loss can be removed from the installation by cooling the current conductor.
A high-voltage switch which is embodied as a switch pole of a three-pole generator switch is described in EP 1 496 534 B1 and EP 1 657 731 A1. This switch has a phase conductor which is arranged in a metal encapsulation and which is heated during operation of the switch in an outgoing generator line on account of resistive current losses. Therefore, the high-voltage switch contains a cooling element with a cooler held on the metal encapsulation. The cooler is fixed on a part of the encapsulation that is embodied as a mounting plate, and has cooling ribs arranged outside the encapsulation. The heat formed in the phase conductor is fed to the cooler by air present in the encapsulation (EP 1 496 534 B1) or by the vapor of a liquid evaporated at the phase conductor (EP 1 657 731 A1). The heat emitted by the cooling of the air or respectively by condensation of the vapor is absorbed by the cooler and emitted to the ambient air via the cooling ribs in an effort to increase current carrying capacity without significantly increasing overall dimensions.